Erik Hardy

Posted 05-30-2017 09:19 PM

OrangeCrush86

Posted 05-31-2017 08:20 AM

OrangeCrush86

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What are your plans for the mechanical side of things?

I will publish a cad drawing for the load cell plates and a bill of materials. So far I have found some 1k lbs load cells for $50 each which gives a 4k lb capacity. For now the plan on the electrical side is to use a Raspberry Pi 3 which gives a lot of options.

luvin_the_rings

Posted 06-02-2017 12:55 PM

Steve Scheifler

Posted 06-02-2017 01:02 PM

Steve Scheifler

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Scales are certainly not cheap but they are relatively low volume so I don't begrudge them the margin, much. But I'll be very impressed if you can create a sufficiently accurate DIY set for your target cost. What are you budgeting for the pads? Perhaps by negotiating a group-buy to make multiple sets it would be possible. Don't underestimate the importance of making those flat and rigid.

OrangeCrush86

Posted 06-02-2017 06:09 PM

Sorry I'm a mechanical guy so I have to ask...why the phone and all the software ??

Have your load cells display the weight, end of story, for $200 I'll walk around to each corner.

Now if your were doing 3d (maybe gps) alignment camber, caster, toe, maybe I can see why you'd need the software.

J~

A few reasons.

1. Besides the fact that I like to make software, the main reason is so that I can sit in the car while taking the weights. My current Proform scale is kind of annoying to look out the window and try to read the tiny display.

2. Other than being able to do extra stuff with the data, like store setups, it's actually cheaper to send the scale data to a phone. It essentially removes the cost of LCD displays.

3. I plan on having a local display option later for people that don't want a phone app, but again, it's extra development time and cost.

OrangeCrush86

Posted 06-06-2017 03:39 PM

OrangeCrush86

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To be clear. This project is mostly focused on making a weighing solution available. Not supplying any parts (unless we had a few people in which case we could split the cost to have some PCBs manufactured).

In other words the software and plans are free. You buy a Raspberry Pi3 and get a PCB (or build your own) based on the schematics. Then you order some load cells that meet your application from Amazon and build the mounting plates yourself. Any mounting plate plans I put up will most likely be whatever is simplest to manufacture in a garage.

Brandon

Posted 06-07-2017 09:18 AM

Brandon

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To be clear. This project is mostly focused on making a weighing solution available. Not supplying any parts (unless we had a few people in which case we could split the cost to have some PCBs manufactured).

In other words the software and plans are free. You buy a Raspberry Pi3 and get a PCB (or build your own) based on the schematics. Then you order some load cells that meet your application from Amazon and build the mounting plates yourself. Any mounting plate plans I put up will most likely be whatever is simplest to manufacture in a garage.

My frugal system is approx. $1,000.00 for scales plus $50.00 for adjustable wood stands for a total of say $1,100.00. The cords are long enough the scale readout box is in the car with me. Get a buddy, each chip in 50% each and be done. I have viewed scales from back in the day which had adjusting screws within the scale. I use a $27.00 water leveling tool which is not included in above cost.

1x PCB = ~$12 - Prototype boards in low quantity can be ordered in minimum of 3 units @ approximately $37 dollars (Optional cost, you could wire the electronics with no board)

8x steel plates = $85 - any local fab shop should have something like this; no leveling mechanism

Misc hardware = $20 - bolts, etc

Each set of plates requires 3 holes to be drilled for mounting load cells that can be done yourself.

Total cost is $361.

That is bare minimum, but we could actually work on this platform and extend functionality etc. I don't know if the other scale companies even have a phone app wireless interface or ability to store measurements etc, but they definitely are not on their entry level products. Honestly with a little more work and another $100 in electronics we could even have wireless battery powered pads.

If anyone has an idea of how to get the cost of the plates lower that would be huge since electronics are already dirt cheap and load cells probably won't be easy to get cheaper.

In the end this is just an experiment for me. It's entirely possible that we can't beat the manufacturers that can keep costs low with mass production.